a. Field of the Invention
The present invention relates to a conductive resin composition which has electrical conductivity and antistatic property and is excellent in processability represented by melt flow index and heat resistance which is a property represented by heat distortion temperature.
b. Description of the Prior Art
Accompanied by high density packaging of electronic equipment, IC parts are mounted on a through-hole substrate in order to increase density. If moisture is adsorbed in the IC parts in the mounting step using flow solder, water vapor generated by heating in the interior of the IC parts, leads to blisters or cracks, and damages the IC parts. As a countermeasure, it has been required, to dry the IC parts at temperature of above 120.degree. C. to remove before the mounting step moisture.
Conventionally, the IC parts drying step is carried out after transferring the IC parts from a tray of conductive polyvinyl chloride resin or styrenic resin to a die-cast aluminum tray. The dried IC parts are delivered after transferring again to the above resin tray. Thus a complex step has been required. In order to simplify the steps and to replace the expensive die-cast aluminum tray, plastics which develop no warpage even in the IC drying step of above 120.degree. C. and are excellent in dimensional stability have been investigated for use a heat-resistant tray for IC parts.
Other electronic accessories such as IC magazine cases, TAB carriers and printed substrate inserting racks are also requried to have heat resistance of 120.degree. C. or above.
High-heat-resistant resin include, for example, polyamide resin, polyester resins and compositions obtained by blending glass fibers with these resins. Any of these resins a crystallinity and hence have a large molding shrinkage and poor dimensional stability. Compositions of amorphous resins such as polycarbonate which contains glass fibers are also used. However, glass fibers cause warpage and inferior dimensional stability.
High-heat-resistant amorphous resin include polyether sulfones, polyarylates and polyethermides. These resins, however, have poor processability.